1. Field of the Invention
The invention relates to a seat for a two-wheeled or three-wheeled vehicle such as a two-wheeled or three-wheeled vehicle. More specifically, the invention relates to a bicycle or tricycle seat having a support web suspended within a rigid metal frame.
2. Description of the Prior Art
Conventional bicycle seats are supported by seat posts which extend upwardly from the seat tubes of the bicycles.
Typically, bicycles are sold with saddle-type rail-based seats which are straddled by the riders"" legs while the bicycles are being ridden. Often, such seats are clamped to upper portions of the seat using clamping collars. One drawback to saddle-type seats is discomfort due to selective compression of the rider""s pelvic region and abrasion of the rider""s thighs.
U.S. Pat. No. 3,874,730 to Marchello proposes a bicycle seat of hammock-like shape. The seat includes a seat frame, preferably formed of straight tubing having opposite ends which are bent upwardly to form legs connected by a straight base. Secured centrally of the base, as by welding, is a mounting stub shaft of sufficient length to be inserted within a conventional bicycle frame seat shaft socket and to be fastened therein and held against movement by a conventional clamping collar. The free ends of the legs are provided with slots which receive ring portions of eye-bolts. These ring portions are received around reduced center bearing portions of cross-pins fastened in place in a rivet-like fashion through aligned holes formed in the legs.
The eye-bolts appear to support a seating strip. More specifically, the eye-bolts are freely journalled through central openings in enlarged central portions of cross bars. The seating strip is preferably formed of a pair of elongated, flexible, stretch-resistant web belts. Opposite ends of the two belts are folded or looped over and fastened by stitches to form opposite end loops which receive opposite free ends of the cross bars. Alternatively, the seating strip may be formed of a single strip of webbing-like material having opposite ends which are similarly looped to receive both of the opposite free ends of the cross bars.
Marchello teaches that his proposal produces a seat more comfortable than conventional saddle-type seats. More specifically, the reference teaches that conventional saddle-type seats are relatively uncomfortable and tend to abrade the legs of the rider during movement of the legs. Marchello claims that the seating strip moves with a rider""s body to substantially eliminate relative motion between the seat and the rider""s body, thereby eliminating uncomfortable friction and abrasion.
One drawback to the bicycle seat proposed in Marchello is that it likely would provide only limited support to a rider. Since the flexible strips are relatively narrow (on the order of two inches, that is, 5 cm), it is suspected that Marchello""s seat would provide direct support for only a small portion of the rider""s buttocks. In addition, Marchello""s FIG. 1 suggests that the flexible strips or webbing-like material would pivot about a horizontal axis when a rider is seated. This suggests that at least a portion of the vertical support provided by Marchello""s seat would be provided by friction between the rider and the flexible strips or webbing-like material. In particular, it is anticipated that a rider would slide or swing within the seat as the rider pedals the bicycle. Marchello""s seat does not appear to be adjustable to accommodate riders of different height or build.
Another drawback to the seat proposed in Marchello is lack of sturdiness. In particular, it would likely be difficult to suspend the flexible strips or webbing-like material tautly between the legs of the seat frame.
With continuing reference to FIG. 7, the frame 26 includes a first lateral bar portion 110, a second lateral bar 112 and a cross-bar portion 114. The first and second lateral bar portions 110, 112 are connected to opposite ends of the cross-bar portion 114 by elbow portions 116 and 118 such that the first and second lateral bar portions 110, 112 extend in substantially parallel directions transverse (most preferably, perpendicular) to the length of the cross-bar 114. The bracket plates 22, 24 are preferably affixed to the cross-bar portion 114 so as to balance the weight of the rigid frame 26 relative to the bracket plates 22, 24.
Chow""s FIG. 6 proposes a variable thickness molded rubber sling seat including a cushion consisting of a one-piece molded rubber form having a front edge and a U-shaped channel positioned about its remaining periphery. A series of notches are present along the rear of the periphery to enhance the flexibility of the cushion. A cylindrical frame formed from a pair of tubular sections coupled together at a binge is sized to fit within the channel in the cushion. When the cushion arm is suspended from the frame in a suitable structure such as a wheelchair, the cushion deflects to conform to the shape of the body seated in it, as the rubber flexes in tension, accommodating the curvature of the body and minimizing the pressure by distributing the resultant forces evenly.
Chow teaches the use of such seats on wheelchairs. The reference does not appear to address seats susceptible of mounting on seat posts for use on bicycles or the like.
There remains a need in the art for a sturdy, comfortable seat susceptible of mounting on a seat post for use on a bicycle or the like. In addition, there remains a need in the art for a seat which can be adjusted to accommodate riders of different height and build.
These needs and others are addressed by means of a seat for a wheeled vehicle having a seat post comprising a clamp for engaging the seat post and a rigid frame supported by the clamp. Most preferably, the rigid frame includes a first lateral bar portion, a second lateral bar portion, and a cross-bar portion connecting the first and second lateral bar portions.
In accordance with one especially preferred embodiment, the seat includes a support web suspended from the rigid frame. The preferred support web sheet defines a first edge, a second edge and a third edge intermediate the first and second edges. The support web preferably comprises a flaccid sheet but might also comprise, for example but not by way of limitation, a solid material or a pliant cushion encapsulated in a flaccid sheet. The support web is coupled to the first lateral bar portion near the first edge, to the second lateral bar portion near the second edge, and to the cross-bar near the third edge.
Most preferably, the support web is a flaccid sheet secured to the rigid frame by means of loops which embrace the bar portions of the rigid frame so as to provide a high degree of tautness and sturdiness. More specifically, the preferred flaccid sheet defines a first loop near the first edge which embraces the first lateral bar portion, a second loop near the second edge which embraces the second lateral bar portion and a third loop near the third edge which embraces the cross-bar portion. In accordance with an especially preferred embodiment, the support web has a free edge opposite to, and parallel with, the third edge.
In accordance with another especially preferred embodiment, the seat includes at least one resilient cushion at least partially surrounds the first and second lateral bars of the rigid frame. Most preferably, this structure comprises a first resilient tube substantially surrounding the first lateral bar and a second resilient tube substantially surrounding the second lateral bar. The preferred cushions or tubes include a foamed polymeric material such as foamed rubber.
The rider preferably sits in an orientation in which the rider""s legs extend past the lateral bar portions of the rigid frame. By means of this arrangement, the rigid frame provides vertical support for the rider while evenly distributing the supporting forces so as to avoid undue pressure on sensitive portions of the rider""s pelvic region. The cross-bar provides support behind the rider""s buttocks when the bicycle is accelerated.
The rigid frame preferably is supported by a bracket mounted on the clamp. More specifically, the preferred clamp includes a block having a through-hole, a split extending from a free surface of the block into communication with the through-hole, a threaded socket extending through the split and a set screw engaging said threaded socket for securing the clamp onto the seat post of the wheeled vehicle. The preferred bracket comprises a pair of parallel bracket plates extending from the cross-bar, each bracket plate including an elbow and an arm portion configured such that the arm portions of the bracket surround the clamp. Most preferably, the seat includes a pair of tie rods extending from the pair of parallel bracket plates toward the first and second lateral bar portions so as to provide azimuthal support to the rigid frame.
The preferred bracket is pivotally mounted on the clamp so as to permit the adjustment of the seat to accommodate riders of different height and build. More specifically, each arm portion of the bracket has at least a first hole and a second hole spaced from the first hole along the length of the arm portion. The preferred second hole has a length along a direction transverse to the length of the arm portion which is greater than a maximum length of the first hole along the same direction. The preferred clamp includes a first journal extending through the block making up the clamp in alignment with the first hole in each of the bracket plates and a second journal extending through the block in alignment with the second hole in each of the bracket plates. A first threaded pin extends through the first journal and through first hole in each leg portion. A second threaded pin extends through the second journal and through the second hole in each leg portion.
The preferred bracket can be secured so as to retain it in a desired orientation. More specifically, one or more nuts engage at least one of the first and second threaded pins. This permits the rider to tilt the bracket and the rigid frame relative to an axis of the seat post and then to tighten the bolts to lock the rigid frame into an orientation which provides maximum comfort to the rider. Most preferably, the arm portions of the bracket plates include additional sets of holes having cross-section substantially the same as those of the first and second holes so as to permit the rider to move the rigid frame forwardly or backwardly relative to the seat post so as to accommodate riders of different heights and builds.